It seems to have done. Please check, is it correct?
At the stage "fold the products into the finished product."
"2. Through the action "Write a value in the additional field of the process product based on the formula"
write to this created add. field -> value with add. process fields (shown on the screen)"
Seems like he did it right. Screen
https://prnt.sc/uh3h2y"3. Using the "copy process product fields" action, write the price_DOP value in the "price" and "process product price" fields
Did. Screen
https://prnt.sc/uh3hta"1. Create an additional field for the product of the process ( price_ADV )"
I don't understand :-( Please elaborate.